Air pump



oct.' 27, v1936. D, GREGG 2,058,441

AIR PUMP Filed Sept. 27, 1953 I @a 33 4/ 7 I llllllllllllllz` IN V ENTUR. y Z4 Da w'o Gre BY www A TTORNEY.

Patented Oct. 27, 1936 UNITED STATES PATENT. OFFICE AIR PUMP ApplicationSeptember 27, 1933, Serial No. 691,218 1 Claim. (Cl. Z39-#152) Thisinvention relates to fluid pumps and more particularly to vane pumps. Invane pumps as heretofore made, the housing is either of the cylindricaltype with short; spring-pressed vanes or of the non-circular conchoidaltype with 'varies extending diametrically of the housing, the shape ofthe housing being defined by the movement of the vane ends. Conchoidal/housings and other non-circular forms are expensive -to manufacture andspring-pressed vanes involvev numerous small parts and introducefrictional losses. l

'I'he present invention contemplates the use of a cylindrical housingwith diametrically extendl5 ing vanes in which centrifugal force is usedto cause the blades. to follow the housing and the blades aresubstantially of the same length as the chordal dimension of thecylinder taken at right angles to a plane including both .the center 0of the housing and the center of the rotor, that is, the blades areslightly shorter than the housing diameter.

An object of the invention is to provide a vane l pump which may becheaply manufactured without sacrificing operating eiciency.

Another object of the invention is to provide a pump with a cylindricalhousing in which the ends of the blades abut at some portion of theirmovement in order to move one of the blades 3Q beyond the center of therotor whereby centrifugal force will cause it to follow the cylindercontour.

Other features and objects of the invention will be apparent from thefollowing description '35 in connection with which a preferred emboditheFigs. 1 to 6, the pump body generally designated at 3 comprises aportion 4 having a cylindrical liner 1 within which is an eccentricrotor G* supported in the reduced portion 5 of thepump body by a bushing9. The rotor is adapted to be driven Referring to the drawing, andparticularly by shaft i3, the squared end I4 of which is pressed into asleeve I1 secured to the reduced portion vI8 of the rotor by a pin I9. Agrease cup 20 is provided for lubrication of the parts, and studs 2|form a convenient means of attachment to the housing of an engine (notshown).

The rotorvB is slotted at 22 and 23 for the reception of two pairs ofvanes or blades 24 havin g cut-out portions 28 to permit the vanes tomove relatively to each other in the diametrally arranged slots 22 and23. The vanes 24 are identical and of a length such that the combinedlength of one pair is substantially equal to the chord of the liner 1that is perpendicular to a plane including the axes of both the linerand the rotor.

The rotor may be driven in either direction but isl shown as rotating inthe direction of the arrowin Fig. 4. Recess 39 in cover 33 for-ms thepump outlet and recess 4l forms the pump inlet. The recesses communicatewith pipes 31 and 39 respectively for connecting the pump to anyinstrument or device with which the pump is to be associated.

During pump operation, as shown in Fig. 6, the horizontal blades 24 havetheir inner ends 29 in contact while the vertical blades are separatedbecause the upper vertical blade has been moved outwardly by centrifugalforce to contact the liner 1, it being understood that each blade willfollow the circular path shown in dotted lines.

To prevent wear on the liner and ends of the vanes, lubricant isintroduced to the pump through a check valve 5l arranged on thecompression side of the pump and which is connected by pipe 52 to anysuitable source of lubricant supply.

In the form of the invention shown in Fig. 7 two vanes 42 and 43 areused which are identical, and to all intents and purposes the same asvanes 24 if their inner-ends 29 were joined'.

In the operation of the pump shown in Figs. 1 to 6, rotation in thedirectionV of the arrows causes fluid to be drawn into the expansionchambers 25 through pipe 38 until the sides of the vanes 24 have passedthe end of recess 4|, after, which it is forcedfrom compression chambers25 into pipe 31 until the vanes have passed beyond the end of elongatedrecess 39. The operation of the pump is Well known, but 'it will benoted that the path described by the ends of the blades is circular, thecenter of the path is at 0, and the vane, remote from the point oftangency of the rotor and the liner 1, moves outwardly in its slot bycentrifugal force. It will also be noted that as each blade moves fromits horizontal position toward the point of tangency that its inner endwill contact the corresponding end of the blade in the same slot andforce it outwardly from the center of the rotor whereby each blade isvpositively started on its outward movement.

In the operation -of the form of the pump shown in Fig. 7. as each bladeapproaches the point of tangency the center of the mass of each bladewill move outwardly from the center of the rotor, and centrifugal forcewill cause the blade to follow the liner. In this form of the inventionthe blade will not contact the housing at the point of tangency;therefore, the clearance between the rotor and housing must be slight.Theoretically, some loss will occur at this point, but by introducinglubricant adjacent the point of tangency in the manner described, theloss of pressure is negligible by reason of the lubricant sealing eect.

While two forms of the invention have been shown and described, it isunderstood that this showing and description are illustrative only andthat the invention is not regarded as limited to the forms shown anddescribed or otherwise, except by the terms of the following claim:

Aaccenti What is claimed is:

A uid pump comprising a body having a cylindrical housing and planesurface'end walls, a radially slotted rotor in said housing mountedeccentric to the housing, said rotor having a reduced extensionrotatably supported in an opening in the body end wall, the other ofsaid end walls being removableand having inlet and exhaust portstherein, a pair of straight sided at blades slidably mounted in eachslot of the rotor, each pair of said blades having a'n overall length,substantially equal to a chord of the housing takters of both thehousing and rotor, said blades being substantially identical and havingcut-out central portions .for permitting relative blade movement, saidblades being arranged to have the sides thereof control the ports in theremovable end wall, a cylindrical member drivably secured to saidextension having a polygonal opening therein, said member and saidextension forming a complete closure for the opening in the body endwall, and a, polygonal drive shaft fitted in the opening of the member.

DAVID GREGG.

